phonet: Check input from user before allocating
A phonet packet is limited to USHRT_MAX bytes, this is never checked during tx which means that the user can specify any size he wishes, and the kernel will attempt to allocate that size. In the good case, it'll lead to the following warning, but it may also cause the kernel to kick in the OOM and kill a random task on the server. [ 8921.744094] WARNING: at mm/page_alloc.c:2255 __alloc_pages_slowpath+0x65/0x730() [ 8921.749770] Pid: 5081, comm: trinity Tainted: G W 3.4.0-rc1-next-20120402-sasha #46 [ 8921.756672] Call Trace: [ 8921.758185] [<ffffffff810b2ba7>] warn_slowpath_common+0x87/0xb0 [ 8921.762868] [<ffffffff810b2be5>] warn_slowpath_null+0x15/0x20 [ 8921.765399] [<ffffffff8117eae5>] __alloc_pages_slowpath+0x65/0x730 [ 8921.769226] [<ffffffff81179c8a>] ? zone_watermark_ok+0x1a/0x20 [ 8921.771686] [<ffffffff8117d045>] ? get_page_from_freelist+0x625/0x660 [ 8921.773919] [<ffffffff8117f3a8>] __alloc_pages_nodemask+0x1f8/0x240 [ 8921.776248] [<ffffffff811c03e0>] kmalloc_large_node+0x70/0xc0 [ 8921.778294] [<ffffffff811c4bd4>] __kmalloc_node_track_caller+0x34/0x1c0 [ 8921.780847] [<ffffffff821b0e3c>] ? sock_alloc_send_pskb+0xbc/0x260 [ 8921.783179] [<ffffffff821b3c65>] __alloc_skb+0x75/0x170 [ 8921.784971] [<ffffffff821b0e3c>] sock_alloc_send_pskb+0xbc/0x260 [ 8921.787111] [<ffffffff821b002e>] ? release_sock+0x7e/0x90 [ 8921.788973] [<ffffffff821b0ff0>] sock_alloc_send_skb+0x10/0x20 [ 8921.791052] [<ffffffff824cfc20>] pep_sendmsg+0x60/0x380 [ 8921.792931] [<ffffffff824cb4a6>] ? pn_socket_bind+0x156/0x180 [ 8921.794917] [<ffffffff824cb50f>] ? pn_socket_autobind+0x3f/0x90 [ 8921.797053] [<ffffffff824cb63f>] pn_socket_sendmsg+0x4f/0x70 [ 8921.798992] [<ffffffff821ab8e7>] sock_aio_write+0x187/0x1b0 [ 8921.801395] [<ffffffff810e325e>] ? sub_preempt_count+0xae/0xf0 [ 8921.803501] [<ffffffff8111842c>] ? __lock_acquire+0x42c/0x4b0 [ 8921.805505] [<ffffffff821ab760>] ? __sock_recv_ts_and_drops+0x140/0x140 [ 8921.807860] [<ffffffff811e07cc>] do_sync_readv_writev+0xbc/0x110 [ 8921.809986] [<ffffffff811958e7>] ? might_fault+0x97/0xa0 [ 8921.811998] [<ffffffff817bd99e>] ? security_file_permission+0x1e/0x90 [ 8921.814595] [<ffffffff811e17e2>] do_readv_writev+0xe2/0x1e0 [ 8921.816702] [<ffffffff810b8dac>] ? do_setitimer+0x1ac/0x200 [ 8921.818819] [<ffffffff810e2ec1>] ? get_parent_ip+0x11/0x50 [ 8921.820863] [<ffffffff810e325e>] ? sub_preempt_count+0xae/0xf0 [ 8921.823318] [<ffffffff811e1926>] vfs_writev+0x46/0x60 [ 8921.825219] [<ffffffff811e1a3f>] sys_writev+0x4f/0xb0 [ 8921.827127] [<ffffffff82658039>] system_call_fastpath+0x16/0x1b [ 8921.829384] ---[ end trace dffe390f30db9eb7 ]--- Signed-off-by:Sasha Levin <levinsasha928@gmail.com> Acked-by:
Rémi Denis-Courmont <remi.denis-courmont@nokia.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
parent
35f9c09f
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